Conceptual Physics (12th Edition)

by
Hewitt, Paul G.

Published by
Addison-Wesley

ISBN 10:
0321909100

ISBN 13:
978-0-32190-910-7

Chapter 27 - Think and Explain: 60

Answer

See below.

Work Step by Step

Particles in the smoke scatter blue light strongly. Against trees near the ground, which provide a dark background, you see the smoke as blue because you mostly see the light scattered by the smoke.
When the smoke is backlit by a bright background (i.e., the sky), what you see is skylight minus the light that is scattered by the smoke. You see the complement of blue: yellow.